Ultrasonic cellular tissue screening tool

ABSTRACT

Ultrasonic scanning and diagnostics for cellular tissue are disclosed. An ultrasonic probe is moved across cellular tissue at a rate that is synchronized with the image capture rate of the ultrasonic scanner, to achieve a contiguous and complete set of scan images of the tissue. The probe can be held in a single position as it is moved across the tissue, or it can be dynamically adjusted during the scan to provide optimal contact with the scanned tissue. The image data are captured and converted to a format that is easily stored and compatible with a viewer. The viewer allows playback of the scanned images in a manner that is optimized for screening for cancers and other anomalies. A location function allows the user to select a point of interest on an individual scan image, and choose another known reference point, and the function calculates and provides the distance from the reference point to the point of interest in three dimensions.  
     The system can be used for virtually any tissue, but can also be optimized for breast cancer screening. A pad of different density may be placed over the nipple to provide a reference point that is visible in the scan images. The breast may be covered with a fabric that is constructed in such a manner to hold the breast in place and reduce ultrasonic scanning errors, as well as holding the pad in place. The location function described above will use the nipple pad as a reference point from which to measure any detected cancers or other anomalies.

[0001] This is a divisional application of U.S. patent application Ser.No. 09/687,128, filed Oct. 13, 2000 in the name of Kevin M. Kelly etal., for which priority under 35 U.S.C. 120 is claimed. The disclosureof U.S. patent application Ser. No. 09/687,128 is incorporated herein byreference.

FIELD OF THE INVENTION

[0002] The field of the present invention is ultrasonic scanning anddiagnostics for cellular tissue.

BACKGROUND OF THE INVENTION

[0003] Ultrasonic probes have been used for scanning cellular tissue formany years. Presently, any medical ultrasound examination, whether ofthe heart, pelvis, abdomen, soft tissues or any other system, is usuallydisplayed as a number of individual frames or pictures from a studyperformed in a dynamic movie-like manner. The usefulness of the scan,however, is dependent on the skill of the operator, who manipulates theprobe by hand while watching the scan images on a monitor to identifyareas of interest. Once these areas are identified, the operator usuallyrecords single or multiple single scan images showing those areas.

[0004] Because the operator must choose a few frames from the largenumber generated during the scan, the process is open to error. Theoperator may fail to select an image of an important finding, or mayselect an image that misrepresents the overall findings. In addition,since the operator is manipulating the probe by hand, and the speed ofthe probe over the tissue cannot be correlated with the image capturerate of the probe, the coverage of the scanned tissue is somewhathaphazard. As a result, the operator does not record a series of imagesthat represent a contiguous and complete set of images for the entirescanned tissue. Nor does the manual operation of the probe allow forentirely uniform coverage of the tissue, even if multiple passes areused.

[0005] A second method of recording ultrasonic examinations is used fordynamic examinations such as echocardiography, where a dynamic recordingis made on videotape. Unfortunately, this analog method is not matchedto the digital sonographic recording of individual frames. Consequently,there is a great loss of detail that prevents the evaluation ofindividual frames, which limits the usefulness of the videotape fordiagnosing tissue anomalies. In addition, the use of separate videotapesfor individual patients is expensive, and creates a storage problembecause of the bulkiness of the tapes. The interpreting physician has noway to vary the speed of playback or to vary the size of the images. Norcan the physician vary the inherent contrast and brightness of theimages, only the monitor settings. These difficulties lengthen thereview time and prevent optimum viewing.

[0006] Specific to screening asymptomatic women for occult breastcancer, there are two methods presently in widespread use, physicalexamination and mammography. Both of these methods are imperfect.Physical examination, whether performed by the woman herself or by aphysician or other health care provider, usually cannot detect cancerssmaller than ½ inch in diameter. Some cancers have to be many timeslarger to be detected. Mammography is unable to detect as many as 30percent of cancers smaller than ½ inch. About 5 to 10 percent of largercancers are mammographically occult. Mammograms also use radiation andnecessitate painful compression of the breasts, which discourage womenfrom having routine mammograms.

[0007] Although not well recognized by the medical community, ultrasoundis very proficient at diagnosing breast cancers if the location of theabnormality is first discovered by another modality, such as mammographyor physical examination. When using ultrasound as a screening method forthe entire breast, however, malignancies are usually difficult to pickout of the background tissue. In the past there have been two schemes touse ultrasound for breast screening, but they failed to gain acceptancedue to their unacceptably low success rate in finding cancers.

[0008] One method was a water bath system with multiple ultrasoundprobes and the breast in a water bath that allowed generation of imagesof the whole breast in consecutive slices. These slices could be viewedin sequence at a rate of one every ten seconds.

[0009] The second method was to videotape-record the scanning performedby a technician examining the entire breast. This method had thedisadvantage of being somewhat haphazard in breast coverage. Thevariable speed of manual motion does not allow the tissue to beuniformly imaged because the speed is not synchronized to the framecapture rate of the ultrasound probe. Videotaping also results in adegradation of the images for the reasons described above.

[0010] To date, no method has been developed to uniformly and reliablyuse ultrasound probes to create a contiguous and complete set of scanimages for an entire area of cellular tissue, such as a human breast.Ultrasound is usually used to investigate areas of interest in cellulartissue that have already been identified by other screening methods suchas mammograms, x-rays, and MRI-scans. Ultrasound is not ordinarily usedas a screening tool for cellular tissue anomalies.

SUMMARY OF THE INVENTION

[0011] The present invention is directed to an improved system ofultrasonic scanning and diagnostics of cellular tissue. A sequence ofcross-sectional ultrasonic images of tissue are generated. The imagesare recorded in sequence. The recorded images may then be manipulated,if desired and may be viewed in rapid succession. Such uses cansubstantially enhance diagnostics.

[0012] Accordingly, it is an object of the present invention to providea system and method that will allow cellular tissue to be reliablyscreened for anomalies by ultrasonic scanning. Other and further objectsand advantages will appear hereafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a block diagram showing the elements of a cellulartissue screening tool and its interconnections.

[0014]FIG. 2 depicts a plan view of a patient platform and probecarrier.

[0015]FIG. 3 depicts a side view of a patient platform and probecarrier.

[0016]FIG. 4 depicts an end view of a patient platform, and the probecarrier holding an ultrasonic probe.

[0017]FIG. 4A depicts a portion of a probe carrier holding an ultrasonicprobe.

[0018]FIG. 5 is a schematic diagram showing a plurality of scan rows ofscan row images made of a right lateral scan of a human breast.

[0019]FIG. 6 is a flow chart describing how the viewing program on thecomputer acquires data from the ultrasonic scanner, converts it intodigital image data that can be used by the viewing program, and createsan image file.

[0020]FIG. 7 is a flow chart describing how a user interface of theviewing program operates to acquire data from the ultrasonic scanner andcreate an image file on the computer.

[0021]FIG. 8 is a schematic of a preferred embodiment of an image filecontaining a plurality of scan row images.

[0022]FIG. 9 is a flow chart describing how the user interface of theviewing program operates during playback of images on the computer.

[0023]FIG. 10 is a flow chart describing the operation of the viewingprogram's location function.

[0024]FIG. 11A is a front view of a fabric covering.

[0025]FIG. 11B is a rear view of a fabric covering.

[0026]FIG. 12A is a plan view of a nipple pad.

[0027]FIG. 12B is a side view of a nipple pad.

[0028]FIG. 12C is a perspective view of a nipple pad.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0029] As shown in FIG. 1, a preferred embodiment is comprised of apatient platform 2 to steady the patient and provide a base for thesupport member 4, the probe carrier 5 connected with the support member4 that is capable of translational movement to guide the probe acrossthe tissue to be scanned, a standard medical ultrasound device 6 with anassociated probe 8, a remote control device 10 that operates the probecarrier 4, a standard computer 12, a connection device 14 between theultrasound device 6 and the computer 12, and a viewing program thatobtains images from the ultrasound device and converts them into imagescompatible with the viewing program and displays the images. The medicalultrasound scanning device 6 with associated probe 8, computer 12, andconnection device 14 are commercially available.

[0030] The mechanical carrier 4 holding the ultrasound probe 8 can beconnected with the ultrasound scanner 6. Synchronization between theprobe holder mechanical carrier 4 and the ultrasound scanner 6 can beemployed while recording the scans.

[0031] Probe Carrier

[0032] In order to obtain substantially parallel and contiguous images,a mechanical device holding the ultrasound probe 8 propels the probeacross the tissue to be scanned at a uniform rate. In a preferredembodiment shown in FIG. 3, the probe carrier is mounted to a patientplatform 16 that steadies the patient during the exam and acts as a basefor the mechanical probe carrier. The carrier carriage 18 shown in FIGS.2 and 3 is comprised of two parallel vertical members attached to rails20 beneath the platform and a horizontal member that is attached to thetop of the two vertical members, as shown in FIG. 4. The rails 20 allowthe carriage 18 to move along the length of the platform, or the x-axis,as shown in FIGS. 2 and 3. Attached to the horizontal member between thetwo vertical members is another vertical member, called the carrier arm22, with the carrier 24 holding an ultrasound probe 8 at its lower end.The carrier arm 22 is attached in such a manner that allows it to movealong both the y-axis and the z-axis, so that it can move both acrossthe patient and nearer/further from the patient on the platform, asshown in FIG. 4. The carrier 24 itself is articulated to hold the probeat any desired angle relative to the patient by rotating about the x andy axes. The carrier 24 holds the probe 8 at a fixed angle duringscanning. In another embodiment, the carrier 24 dynamically angles theprobe 8 during the scanning process to keep it perpendicular to thepatient's skin (or any other preferred orientation).

[0033] To protect the carriage assembly when not in use, and to preventthe patient from becoming entangled in it when first lying on theplatform, the assembly is housed in a “garage” 26 at one end of theplatform 16. In a preferred embodiment, the carriage 18 is propelledalong the x-axis of the platform 16 during scanning by one or moremotors that are controlled by a microprocessor. The carrier arm 22 isalso moved along its two axes during scanning by one or more motorscontrolled by one or more microprocessors. The microprocessor(s) can beseparate from the computer that operates the viewing program (describedbelow), or the computer can be used for this purpose. The carrier arm 22moves along the z-axis to maintain consistent contact between the probe8 and the patient's skin during scanning. The carrier arm 22 maintains aconstant pressure of the probe 8 on the patient, with a user-selectedpreset value. This pressure is monitored during the scan and an overridefunction will move the carrier arm 22 up and away from the patient inthe z-axis if a maximum pressure level is detected. In anotherembodiment, the operator will maintain the pressure manually during thescanning process, and the pressure may be measured using pressuretransducer(s) in close proximity to the probe head. The carrier arm 22will move upward to clear the patient at the end of the scan. A manualoverride on the remote control 10 is also available to move the carrierarm 22 away from the patient when there is a panic or emergencysituation.

[0034] In other embodiments, the carriage and carrier arm can be eitheron a parallel track arrangement (one sided or multi-sided), or becomprised of an articulating arm or some other contrivance, locatedover, underneath or adjacent to the patient (with or without the use ofa patient platform) positioned either upright or prone. The carrier armneed not be supported by a carriage assembly connected to the patientplatform, but could be independently suspended from the ceiling, wall,or floor. The carrier mechanism could be similar to carriage mechanismscurrently used to support x-ray machines, with means added to providethe requisite movement of the probe. The probe may be supported andpropelled by the mechanical carrier by any means (manually,mechanically, electrically, hydraulically, pneumatically or by any othermeans, with or without control feedback), or any combination of methods.These methods, singularly or combined may be utilized to control theprobe in the X, Y and Z-axes. Gravity may also be employed to providethe requisite pressure of the probe on the patient, or assist in thepropulsion of the probe across the tissue.

[0035] The probe may be designed as a permanent or removable componentof the mechanical carrier. The carrier may be designed with or withoutan onboard integrated ultrasound machine, ultrasound probe, and orultrasound probe interface.

[0036] The carrier 24 can be articulated to change the angular positionof the probe 8 prior to or during scanning either manually, or by one ormore motors controlled by one or more microprocessors. Themicroprocessor(s) can be separate from the computer that operates theviewing program (described below), or the computer can be used for thispurpose. The pitch axis tilts the probe 8 forward and backward, rotatingit about the y-axis, and the roll axis tilts the probe 8 left and right,rotating it about the x-axis. The pitch and roll axes maintain fullcontact between the probe and the skin surface by maintaining the probe8 at a perpendicular angle to the skin, to allow for optimal ultrasonicimaging.

[0037] In an embodiment where the probe's angular position is adjustedautomatically during scanning, the pitch and roll adjustments aretriggered by one or more displacement transducers positioned around theultrasound probe 8. In this embodiment, all the data related to theposition and angle of the probe 8 are provided to the viewing program toallow the images to be correlated with their corresponding location onthe patient. The position data allow the program to compensate for theoverlapping of, or gaps between images. The measurement system can be byany means or convention and may consist of any or all of X, Y, Z-axesand/or the probe angular position.

[0038] The speed of the carrier 24 holding the probe 8 is preciselycontrolled by a microprocessor, and the speed is correlated with thecapture rate of the ultrasonic scanning device 6. The uniform speed ofthe carrier 24 results in images that are uniformly spaced, which allowsthe viewing program (discussed below) to calculate the position of aselected point on any image. In an embodiment where the probe is held ata fixed angle during the scan, the uniform spacing is all that isnecessary to determine the position of each frame of the scan on thepatient. The ultrasound scanning device 6 acts as a controller incommunication with the probe 8 to sequentially activate the probe 8 asit moves across the tissue, but any other controller could be used toactivate the probe, including a computer linked to the probe or thescanning device or both.

[0039] When used for breast tissue scanning, the operator will determinethe amount of area of the breast for scanning. In current practice, thewidth of the tissue scanned by the ultrasound probe is generally toosmall to capture an image of an entire organ, such as the breast. As aresult, several adjacent passes are performed to provide completecoverage. Each pass (called a scan row) will have some overlap with thepreceding pass, to achieve full coverage and eliminate the potential formissing features at the fringes of the scan. Prior to each successivepass, the carrier arm 22 lifts away from the patient, moves along they-axis across the breast and along the x-axis to the top of the breastto position itself for the next scan row, then lowers itself along thez-axis onto the patient.

[0040] A scan row contains a plurality of individual images or frames,typically about 200 to 300 for a breast. FIG. 5 depicts how the frames28 in scan rows 30 are aligned on a typical breast scan, but forclarity, no overlap is shown. A scan row 30 can be thought of as a stackof photographic slides, each slide representing an individual frame 28.The frames 28 are evenly spaced. This may be accomplished by uniformmotion of the probe 8 and uniform timing of the scans. The frames aremost conveniently substantially parallel to each other.

[0041] In another embodiment, the probe's 8 angular position isdynamically adjusted during scanning to follow the contours of thetissue being scanned. In that embodiment, the tops of the frames areevenly spaced, and the tissue contours will be sufficiently gentle thatadjacent frames will remain substantially parallel to each other,although they may differ by as much as a few degrees. Although adjacentframes within a single scan row are substantially parallel, frames maybecome progressively less parallel as they are separated by anincreasing number of frames. Frames in two adjacent scan rows are notnecessarily substantially parallel.

[0042] In a preferred embodiment, two breasts are scanned in foursegments, each segment consisting of one-half of a breast. Each segmentconsists of multiple scan rows 30, with the first scan row aligned atthe center of the breast over the nipple and successive scan rows beingprogressively further from the nipple. FIG. 5 depicts a series of scanrows 30 that make up one segment. In other embodiments, each breast maybe scanned in one or more segments, with the scan rows progressingacross the entire breast from lateral to medial, or vice-versa.

[0043] Viewing Program

[0044] The viewing program preferably has the following overallfeatures:

[0045] a) It allows the entry and storage of demographic and otherwritten data about each patient.

[0046] b) It extracts multiple series of the scanning data from theultrasound scanning device either as a single image, a completed dataset from a cine loop or as real-time continuous data from videostreaming.

[0047] c) It assembles this data into a single or a number of individualframes for viewing.

[0048] d) It may present the multiple data series as descriptive titleson a content page for subsequent review by the operator.

[0049] e) In the case above, when each descriptive title is selected,the corresponding data series is loaded and displayed by the viewer.

[0050] f) It is able to present the frames from each data set asindividual images that are displayed on a monitor at a variable rate.This rate can be sufficiently fast to impart a movie or cine-likequality to the images. The frames can be also displayed at a slow rateor even as still pictures for more intense study.

[0051] g) It is able to display the images at variable magnification andwith a variety of imaging enhancements that make anomalies morepronounced and visible, including variable contrast and brightness,gamma correction, etc.

[0052] h) It acts as a recorder, able to store the information from eachpatient scan on a data storage device such as a computer hard disk andon any temporary or permanent data storage device such as compact disks(CD's).

[0053] i) Along with the patient scan data, it may incorporate astand-alone viewer program on each CD or other storage media.

[0054] j) It allows the transfer of single or multiple images to theInternet, printers or other image programs, such as PowerPoint orPhotoShop.

[0055] k) It allows for the translation of the scan data into the DICOMformat for use by other proprietary software.

[0056] l) During image review, it emits an audible signal, a visualsignal, or both, that identifies the end of each scan row, segment, andbreast, to identify the relative position within the scan data withoutrequiring the user to look away from the images in order to assess therelative position within the image sequence.

[0057] A preferred embodiment of the viewing program (or viewer) is astreamlined, monolithic, 32-bit Windows application designed to run onWindows 95, Windows 98, NT 4, and Windows 2000. A preferred embodimentis implemented to interface with and acquire data from the GeneralElectric Logiq 700 medical ultrasound scanner. The viewing programcould, of course, be written to run on other types of computer systemsand future versions of operating systems, and to interface with othertypes of scanning devices. As used in the claims, “computer” genericallyrefers to any suitable device using one or more microprocessors toprocess data.

[0058] The viewing program's monolithic structure and relatively smallsize allow it to be bundled with the image data for ease of transportand viewing flexibility. In most cases, complete scan data for a patientand the program can be placed on a single CD, allowing the user totransport a number of patient scans in a relatively small package, andview them on any computer that is compatible with the software on theCD. Although it would be even more convenient to transmit scans viae-mail, the current speed and size limitations of e-mail make sendingthe entire scan impractical. If desired, however, the viewing programcan select small segments of the scan data and bundle it with theviewing program, for a small data package that is practical to send viacurrent e-mail systems. Other delivery options could also be utilized,such as streaming video over the internet, or discrete file downloadsusing file compression to speed download time. To satisfy medicalregulatory requirements, a lossless compression technique should beused, such as Portable Network Graphics (PNG), or other losslessschemes.

[0059] In other embodiments, the viewing program could be designed tooperate solely on a computer on which it resides, or it could beresident on a server in a client-server environment. The program couldalso be non-monolithic, using Java or a similar language, in anetwork-centric environment. Given the rate at which softwareprogramming and computing hardware are developing, there are limitlessvariations of how to implement the software and hardware to achieve thedesired result of the viewing program.

[0060] In a preferred embodiment shown in FIG. 1, the viewer programcontrols the scanning operation and data offloading via a connectiondevice 14, such as a network TCP/IP interface. Other connection devicescould be used, or with certain scanners, none may be needed. The GeneralElectric Logiq 700 ultrasonic scanning device has an internal bufferthat can store a finite amount of image data before offloading isrequired to clear the buffer for another scan. Other scanning deviceshave no such buffer, but instead provide an output of streaming data asthe scan is being performed. Although a preferred embodiment uses ascanning device with a buffer, the program is capable of acquiring imagedata from scanning devices that continuously offload streaming data.Other embodiments with different data outputs from the scanning devicecan also be used with the viewing program.

[0061] In a preferred embodiment, the computer acts as a receiver andrecorder for the ultrasonic images obtained from the ultrasonic scanningdevice. As shown in FIG. 6, a preferred embodiment uses a handshakesequence between the viewer and scanner to begin the scan acquisitionprocess 32. The viewer then invokes the scanner to clear its internalframe buffer 34 and then to acquire a scan row to its internal buffer36. The viewer freezes the scanner buffer 38, determines the number offrames in the buffer, their dimensions and pixel format 40, initializesa new scan row in the image file 42, reads individual frames from thebuffer 44, counts the frame format 46 and writes them into the imagefile 48 on a data storage device. It then repeats the acquisitionprocess until all the frames in the scan row are processed 50, andterminates the scan row in the file 52. It then starts all over withadditional scan rows until the entire scan is acquired in the image file54. A preferred embodiment of the viewer uses a proprietary image fileformat, which contains a header for patient information and scaninformation (“image file”). In another embodiment, the viewing programconverts the image data into a DICOM format, which also contains aheader for patient information and scan information. DICOM stands for“Digital Imaging and Communications in Medicine,” and is a standarddeveloped by ACR-NEMA (American College of Radiology-National ElectricalManufacturer's Association) for communications between medical imagingdevices.

[0062]FIG. 7 is a flow chart showing the user interface for the datatransfer process from the scanner to the computer. The user creates anew file by choosing from the file menu 56, specifies a name for the newfile 58, enters the patient data and relevant information 60, makes aselection from the data menu 62, and specifies what segment of thebreast is about to be acquired 64. The user then begins the acquisitionprocess 66, and frames are then offloaded sequentially from thescanner's frame buffer via a connection device 14, such as a networkinterface, then normalized, compressed losslessly (if desired) andwritten sequentially to the image file, said file recorded on a datastorage device. When all buffered frames are processed, the viewerterminates the constructed row in the image file 68. Another scan rowcan then be acquired and so on, or the interface to the scanner may beterminated 70.

[0063] For offloading streaming data, the program performs a real-timewrite-through. The program queries the scanner for the image formatbefore beginning the acquisition. Then it buffers a single frame at atime and writes that one frame to a data storage device, beforeobtaining another frame through the sockets interface.

[0064] Acquiring The Data

[0065] In a preferred embodiment, the viewer creates (and subsequentlydisplays) proprietary image files, the format of which consists of afile header 72, a patient information block 74, and zero or more blocksof scan row frames 76, as shown in FIG. 8. The patient information block74 contains not only information about the patient, but also informationabout the scan itself, such as the depth and width of the scan, lengthof the scan row, speed of the carrier during the scan, the number offrames per second captured by the scanner, the spacing between eachframe, etc.

[0066] In another embodiment where the probe's angular position isdynamically adjusted during the scan, the viewer program records on adata storage device the angular position of each frame and otherinformation for each frame. The angular position data can be provided tothe viewer program though the scanner 6, from sensors attached to theprobe 8 or the carrier 5, or from an intermediary computer program thatgathers this data.

[0067] Rows appear in the image file in the order they are acquired, notnecessarily the order in which they will ultimately be displayed by theviewer. Any number of scan rows may be included in an image file andthere is no limit to the size of an image file. The data in an imagefile are laid out in such a manner that frames within a row are advancedin the order in which they will be displayed. This enables the viewer todo efficient read-ahead buffering during display for optimal viewingsmoothness.

[0068] The viewer is implemented to be largely independent of theparticular scanner hardware with which it is paired. A specific modulewritten for each scanner is responsible for “normalizing” data from theinternal format used by that particular scanner to the format usedwithin an image file. Scan row frame elements stored in an image fileare written in a format optimized for rapid rendering during display. Ina preferred embodiment, the viewer is run on computers using a WIN 32operating system, and scan frames are written to image files in an 8-bitformat that closely mirrors 8-bit grayscale Windows DIB(device-independent bitmap) format. This allows the images to beefficiently displayed on a Windows computer with practically no routinetranslation.

[0069] A preferred embodiment pairs the viewer program with the GeneralElectric Logiq 700 ultrasound scanner. To translate frame data from theformat used internally by the Logiq 700 or any other scanner, eachspecific normalizing filter performs several operations to the formatused by the viewer when creating image files. In the Logiq 700, theseoperations include the following:

[0070] 1. Byte #3 (the fourth byte) of every D-word is stripped

[0071] 2. Transparent color value 255 is normalized to 0

[0072] 3. Scan lines are inverted

[0073] 4. Byte ordering is changed from “Big Endian” to “Little Endian”

[0074] 5. Scan lines are aligned to 4-byte boundaries

[0075] When interfacing with a different scanner device, differentnormalization operations would be appropriate.

[0076] Displaying The Images

[0077] After acquiring, converting, and storing the scan data, thesecond major task of the viewer is to display the scan images. Theviewer opens a previously created image file and renders sequential scanrow frames within its interface in a “movie-like” manner. In a preferredembodiment for breast cancer screening, a breast can be divided into twoparts; from the nipple toward the axilla is the lateral half, and fromthe nipple toward the sternum is the medial half. A set of scan rows foreach breast half is called a “segment,” and thus there are four segmentsfor two complete breast scans. The viewer arranges all scan rows suchthat they are displayed beginning with right lateral scan rows (arrangedsuch that subsequent right lateral rows are progressively more lateral),and then proceeding to right medial scan rows (arranged such thatsubsequent rows are progressively more medial). The viewer then proceedsto left medial scan rows, and then to left lateral scan rows. Althoughthe above arrangement of the scan rows is implemented in a preferredembodiment, different arrangements could be used in other embodiments.

[0078] The viewer's user interface provides access to these features andcapabilities:

[0079] 1. Play, pause, and reset scan row playback

[0080] 2. Step forward and backward between sequential frames

[0081] 3. Adjust playback frame rate

[0082] 4. Jump forward and backward between scan rows

[0083] 5. Export single frames and sets of frames as standard bit-mappedimages

[0084] 6. Select a start point and end point in the frame sequence andloop playback over that selected frame scan

[0085] 7. Adjust the brightness and contrast of displayed frames

[0086] 8. Apply imaging enhancements to make features or anomalies morevisible

[0087] 9. Print single frames and sets of frames

[0088] 10. Measure features displayed on certain frames, given thephysical height and width of the frames

[0089] 11. Calculate the physical location of a point of interest (POI)on a particular frame given a reference point (RP) (on the same frame ora different frame), the physical dimensions of the frames, theZ-coordinate spacing between frames and the X-coordinate overlap offrames on subsequent scan rows

[0090] 12. Alter the frame magnification

[0091] The user interface for the viewing program looks and operates inlargely the same manner as commercially available digital video players,such as Microsoft Windows Media Player, with buttons for Play, Pause,Stop, a slider bar to move back and forth within segments, etc. Theplayback features utilize standard Windows input/output operationscommonly used in digital video applications. A generalized flow diagramshowing the user interface steps for playback operation is shown in FIG.9.

[0092] One of the viewer features is the ability to determine thephysical location (on the patient) of any point on any frame given anyselected reference point on the same frame, or on a different frame. Forexample, if a physician finds an abnormality on one frame, he needs tothen be able to locate some prominent feature elsewhere in the framedata, i.e., the nipple or a temporary mark placed by the operator, andthen find the position of the abnormality relative to that referencepoint.

[0093] The user interface for the location feature operates as shown inthe flowchart in FIG. 10. The user marks the point-of-interest (“POI”)on a particular frame being viewed 78 by double-clicking it with thecomputer mouse 80. An overlapped window then appears, and within thatwindow a small display pane shows “thumbnail”-sized sonograph framestaken from the scan rows (actually, the same row “segment”) in which theabnormality lies 82. The user can then traverse through the thumbnailedframes until he locates a reference frame containing a reference point(“RP”) he wishes to use 84. In the case of a breast scan, the RP willoften be the nipple, which can be positively identified by placing aspecial pad over the nipple during the scan, readily identifiable on theviewer image. The user can then mark a point on that reference frameusing the mouse 84. The viewer program immediately calculates the firstposition relative to the reference point 86 and displays the results (inboth textual and graphical format) to the user 88. The user then closesthe dialog box to end the function 90.

[0094] To implement the location feature, the viewer takes advantage ofthe data known about the scan, which is written in the image file'sheader as part of the data acquisition process. Such informationincludes the width of the frame, and the distance between subsequentframes in a particular scan row, and the offset between scan rows.Within an individual frame, the location function calculates theposition of a user-selected point by proportional math, using the numberof image data points (pixels) in the height and width, and the size ofthe frame, to calculate the distance of the point from the sides of theframe. The program counts the number of pixels across the width of theframe, then the user-selected pixel position number is multiplied by theframe width and divided by the total number of pixels. For example,assuming the frame width is 4 centimeters, the program counts 400 pixelsacross that width, and the user selected a point at pixel position 100:100*4 cm/400=1 cm. So the selected point is 1 centimeter from the sideof the frame. The program then performs a similar calculation todetermine the selected point's distance from the top of the frame. FIG.10 depicts this process and also shows how the location functiondetermines the distances and angles from a user-selected point ofinterest (POI) to a user-selected reference point (RP), using the knownvalues and simple trigonometry 86. In breast cancer screening, the POIis usually a suspected cancer, and the RP is the nipple.

[0095] The uniform motion of the carrier results in evenly spacedframes, and thus the distance from a reference frame to a particularframe is calculated by counting the number of frames between them andmultiplying by the spacing 86. In addition, the overlap of each scan rowis known, and thus if the RP is in a different scan row than the POI,determining the location is a simple matter of determining the overlapand measuring the distance, and using trigonometry to make any angularand remaining distance calculations 86. Therefore, counting the framesfrom the RP and taking into account their overlap provides the locationof each individual image.

[0096] In a preferred embodiment where the angular position of the probeis dynamically adjusted during the scanning process, the viewing programobtains each frame's angular position during the scan, along with theother information described above. Using that information, the programagain uses simple trigonometry to calculate the distances between the RPand the POI.

[0097] Another feature of the viewer is its ability to accuratelymeasure the distance between two user-selected points on a single frame.This allows the user to measure anomalies or features found in theimages. The process for measuring is very similar to the locationfunction process. Using the known values for frame depth and width, themeasuring function uses proportional math to determine the distancebetween the two points. To measure diagonally across a frame,proportional math is used to determine the lengths of the triangle legs,and simple trigonometry is used to calculate the length of thehypotenuse, which is the distance between the points.

[0098] Carrier-Less Embodiment

[0099] It is possible to obtain the sequential scans without the use ofa carrier. The probe is coupled with sensors to provide both locationand orientation data that is correlated with each individual frame. Theterm “coupled” means the sensors could be attached to the probe itself,or used to track the probe's movement without actual attachment. Thislocation and orientation sensor system can provide feedback to theoperator to move the probe over the tissue at the correct speed, and tostart each scan row in the correct position. This will allowsufficiently complete coverage of the tissue without the need for amechanized carrier. Alternatively, to obtain relatively uniform spacingof the frames, the speed sensor on the probe can signal the ultrasoundscanning device to vary the frame capture rate to match the speed of theprobe as it is moved across the tissue.

[0100] This carrier-less embodiment does not necessarily rely on theprecise movement of the carrier to provide uniform spacing between theframes of a scan row in order to calculate distances between frames.Because location data are available for each frame, the locationfunction of the viewer can use the location information of the POI frameand compare it to the location information of the RP frame, and make therequisite distance and trigonometric calculations to determine thedistances from the RP to the POI.

[0101] The location and orientation sensor system can be arranged in avariety of implementations. A simple inclinometer can be used todetermine the orientation of the probe in two or three axes. Thelocation of the probe can be tracked by an inertial sensor system, or alaser or infrared system, or a radio frequency local positioning system.Alternatively, a simple wheel device could be used to measure distancesas well as the speed the probe is being moved over the tissue.Alternatively, an optical movement sensor, such as those commonly usedin optical mice, or a laser interferometer, could be attached to theprobe to track its movement. When used for scanning breast tissue inconjunction with a covering, the covering could be made of some type offabric that is compatible with an optical movement sensor. All of thesesystems could use a point on the body as a reference location, such asthe nipple when the system is used for breast scanning.

[0102] Method For Tissue Screening

[0103] The above-described devices, the probe, scanner, carrier, andviewing program, can be combined to provide a method to scan foranomalies in cellular tissue, such as cancers. The tissue is scanned,and the user views the images on a computer, rapidly scanning throughthe images in a “movie-like” fashion. This technique causes anyanomalies in the tissue to become visible during the rapid sequentialplayback, as they distort or disrupt normal fibrous planes or sheets.The user can then run the images back and forth until the framecontaining the anomaly is found, and the user can mark that anomaly andlocate it using the location function of the program. Follow-up studiescan be performed using the location information, including a morefocused ultrasound investigation, biopsy, etc.

[0104] Individual images can be manipulated using image software such asPhotoshop, using filters and other manipulation techniques to enhancethe appearance of the anomalies and make them more visible. In addition,a variety of image enhancement algorithms are commonly known in the artand the viewer program allows them to be used “on the fly” as the imagesare displayed in rapid succession.

[0105] It is anticipated that the image review process could eventuallybe automated, once software is developed to identify any anomalies. Ifnecessary, the user could then study the images to determine theaccuracy of the software's identification.

[0106] For scanning breast tissue specifically, a preferred methodologyis as follows. The mechanical probe carrier is used, and depending uponthe size of the probe, the breast may be scanned in strips or in itsentirety, in either multiple passes or a single pass, respectively. Thebreast may be scanned with or without a covering. FIGS. 11A and 11B showa bra-like covering 92 that may aid in holding the breast in positionfor screening, as well as assisting in uniform integrity of imagegathering by reducing information loss from ultrasonic shadowing. Thecovering also provides some modesty for the patient. Current ultrasoundtechnology requires the use of sonographic coupling agent, usually agel, to exclude any air between the probe and the skin. Therefore, anysuch covering would have to be capable of absorbing the gel, and berelatively transparent to ultrasonic energy. The covering could bepre-impregnated with the coupling agent, or the agent could be appliedby the operator just prior to the scan, or both. To avoid having thepatient pull a gel-soaked covering over her head after the scan iscompleted, a preferred embodiment of the covering is designed todismantle after use. The covering is equipped with a seam in the back 94that is constructed with chain stitching so that the covering may beremoved by slipping it off the patient's arms. Chain stitching issimilar to that used on bags of dog food and charcoal, where thestitching is easily pulled out just by pulling on one end. The shoulderseams 96 could also be made with chain stitching to further easeremoval. Since a preferred embodiment of the covering is designed to bea single-use item, the covering could be cut off with scissors withoutthe need for special stitching. Zippers, hook and loop (velcro™), orother fasteners could also be used to ease the putting on or removal ofthe covering, and would allow the covering to be re-used. A preferredembodiment uses a stretch fabric for the covering, but any suitablematerial that can conduct or pass through ultrasonic energy could beused.

[0107] A nipple pad is placed on each of the patient's nipples toprovide a reference point on the images. The nipple pad shows up on thescan images due to its ultrasonic characteristics that distinguish itfrom the breast tissue. The nipple pad has the added benefit of reducingultrasonic shadowing. FIGS. 12A, 12B and 12C depict a preferredembodiment of a nipple pad, which is made of an ultrasonicallyconductive material, such as a solid gel. A preferred embodiment of thepad is approximately 40 mm in diameter and varies in thickness from 1 to4 mm, but other sizes could be used. Larger and thicker gel pads arecommercially available for isolated ultrasound scans, where offsettingthe probe from the tissue is advantageous. As shown in FIGS. 12A, 12Band 12C, the circular pad is tapered to an edge about the full peripheryof the pad, and has a very smooth surface. The edge of the pad is thickenough to resist tearing, yet thin enough to allow the ultrasound probeto traverse its periphery during scanning without dislodging the pad orcausing an ultrasonic shadow at the pad's edge. The pad may be held inplace by positioning it beneath the above-mentioned fabric covering.

[0108] Another methodology can be used to obtain the images, without theuse of a mechanized probe carrier, as described above. Again, thecovering and nipple pad may be used.

[0109] As described above, the images are reviewed in a rapid sequentialfashion, imparting a sense of motion through the breast tissue. Thereviewer can observe or detect a disruption of the normal breastarchitecture through comparative image analysis or observation. Themethod has advantages over other ultrasound scanning techniques,including the following:

[0110] 1) Parallel and contiguous images are obtained, optimizing thecoverage of the breast tissue and improving the appearance of the imageswhen viewed in a “movie-like” fashion.

[0111] 2) The entire breast is imaged in a uniform and reproduciblemanner.

[0112] 3) The images may be maintained and reviewed singularly, in stripform, or assembled to represent an entire breast, such as 3-Dreconstruction.

[0113] Accordingly, an improved ultrasonic cellular tissue screeningtool is disclosed. Although embodiments and applications of thisinvention have been shown, it would be apparent to those skilled in theart that many more modifications are possible without departing from theinventive concepts herein. The invention, therefore, is not to berestricted except in the spirit of the appended claims.

What is claimed is:
 1. A method for screening cellular tissue,comprising ultrasonically scanning the cellular tissue in closelyspaced, sequentially adjacent images; recording the images in sequence.2. The method for screening cellular tissue of claim 1, ultrasonicallyscanning the cellular tissue creating a quantity of adjacent images inthe magnitude of about 1×10².
 3. The method for screening cellulartissue of claim 1, ultrasonically scanning the cellular tissue being ofimages mutually displaced substantially normally from one another. 4.The method for screening cellular tissue of claim 1, further comprisingviewing the recorded sequentially adjacent images in rapid succession.5. The method of claim 4, further comprising using imaging enhancementsto create increased contrast depicting density variations.
 6. A methodfor screening cellular tissue, comprising operatively coupling alocation and orientation sensor system to the ultrasound probe; movingthe ultrasound probe across the tissue to generate sequentiallyadjacent, closely spaced images; collecting the sequentially adjacentimages with an associated ultrasound scanning device; recording imagesgenerated by the ultrasound scanning device; recording location andorientation data from the sensor system for each image.
 7. The methodfor screening cellular tissue of claim 6, ultrasonically scanning thecellular tissue creating a quantity of adjacent images in the magnitudeof about 1×10².
 8. The method of claim 6, further comprising viewing therecorded sequentially adjacent images in rapid succession.
 9. The methodof claim 6, further comprising using imaging enhancements to createincreased contrast depicting density variations.
 10. The method forscreening cellular tissue of claim 6, ultrasonically scanning thecellular tissue being of images mutually displaced substantiallynormally from one another.
 11. A method of detecting breast tissueanomalies comprising ultrasonically scanning the breast tissue insequentially adjacent images; recording the images in sequence; viewingthe recorded sequentially adjacent images in rapid succession.
 12. Themethod for screening cellular tissue of claim 11, ultrasonicallyscanning the breast tissue being of images mutually displacedsubstantially normally from one another.
 13. The method of claim 11,further comprising using imaging enhancements to create increasedcontrast depicting density variations.
 14. The method for screeningcellular tissue of claim 11, ultrasonically scanning the cellular tissuecreating a quantity of adjacent images in the magnitude of about 1×10².15. The method for screening cellular tissue of claim 14, ultrasonicallyscanning the cellular tissue creating 200 to 300 adjacent images. 16.The method for screening cellular tissue of claim 11, ultrasonicallyscanning the cellular tissue including multiple, substantially parallelscans of sequentially adjacent images.